1. The Field of the Invention
The invention generally relates to optical reflectometry. More specifically, the invention relates to simplifying apparatuses and methods used in optical reflectometry.
2. Description of the Related Art
Modern day computer networks allow for transmissions of large amounts of data between computer terminals. Data may be transmitted on a network across a number of different mediums. For example, data may be transmitted across traditional copper wire based cables. However, copper wire based cables are subject to limitations that are making them less attractive as a solution for many modern networks. Specifically, the copper wire based cables are limited in the amount of data they can carry in a given time period and the length that the data can travel. As computer technology continues to increase in the amount of data that can be produced in a given time period, other types of cable with higher capacities and longer transmission distances may be desirable.
One type of cable that is capable of higher data transmission rates over longer distances is fiber-optic cable. Fiber-optic cables are plastic or stretched glass cables that carry data signals in the form of light. Light signals can propagate on fiber-optic cables at higher speeds and for longer distances than electronic signals on copper wire based cables. Further, fiber-optic cables are potentially lighter weight and less expensive that their copper based counterparts. Thus, fiber-optic cables are steadily becoming a more popular choice for communication networks.
While fiber-optic data signal are optical or light signals, data signals at computer terminals generally continue to be electronic data signals. The electronic data signals being sent by a computer terminal are therefore converted using an electro-optical transducer, such as a laser diode or light emitting diode (LED) that converts the electronic data signals to corresponding optical data signals. To receive a signal from a fiber-optic network, a computer terminal converts the optical data signal to a corresponding electronic signal using an opto-electronic transducer, such as a photodiode and post-amplifier.
Fiber-optic cables or optical fibers are one type of optical waveguide. An optical fiber, or other waveguide, may have various occurrences along the length of the fiber that affect the performance of the fiber. For example, various defects, cracks, breaks, bends, and the like may exist along the length of the fiber. Each of these occurrences can degrade the performance of the waveguide by causing reflections which reduces total power and causes harmful interference. Other occurrences such as connectors and joints can also cause harmful reflections.
It is often useful to be able to detect occurrences along the length of an optical waveguide. This can be done using optical reflectometry. Optical reflectometry involves sending an optical signal from a discrete optical source, such as a VCSEL, onto a waveguide and detecting reflections caused by occurrences using a separate discrete optical detector, such as a photodiode. To accomplish this, a fairly complicated arrangement of optical components is used. An exemplary prior art example of an optical reflectometry apparatus is illustrated in FIG. 1. FIG. 1 illustrates a laser 102 that emits an optical signal. The optical signal optionally is passed through an isolator 104, a fiber coupler 106, and a beam splitter 108 where it is propagated onto a fiber 110. Occurrences associated with the optical fiber 110, such as defects in the fiber, breaks in the fiber, bends in the fiber, connections to the fiber, etc., cause reflections back towards the beam splitter 108. The beam splitter 108 causes a portion of the reflection to be directed back towards the laser 102, and a portion to be directed through a fiber coupler 112 to a detector 114, such as a photodiode. Notably, the laser 102 and detector 114 each function as individual systems performing a specific task and are intentionally isolated from one another through the combination of the beam splitter 108 and the isolator 104 which prevents reflections from reaching the laser 102.
The number of components used in present optical reflectometry applications has an adverse effect on the cost and size of meters and equipment used optical waveguide evaluations. As such, a simpler, more cost effective solution would be desirable.
The subject matter claimed herein is not limited to embodiments that solve any disadvantages or that operate only in environments such as those described above. Rather, this background is only provided to illustrate one exemplary technology area where some embodiments described herein may be practiced.